JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">container</div>
 <div id="loading-img"></div>
 <button id="button">Submit</button>

CSS

#loading-img {
	background: url(http://web.bogdanteodoru.com/wp-content/uploads/2012/01/bouncy-css3-loading-animation.jpg) center center no-repeat;
    display: none;
    height: 100px;
}
.container{
    background: #000;
    color: #fff;
}

JavaScript

$("#button").click(function() {
    $(".container").css("opacity", 0.2);
   $("#loading-img").css({"display": "block"});
});